It has actual source for the worker. We aren't worried about it being leaked because we are not particularly trying to hide it in the first place. We will probably make source available to paying customers on request if they want to verify that their sensitive data only moves between self-hosted worker and self-hosted client.

The other reason is that internally we've always thought that we'd eventually gravitate to an open model when the time is right i.e. at least until after we've figured out the product.